A Yute Air plane that crashed in Southwest Alaska last month was flying at a low altitude and appeared to have struck a tree moments before crashing into the Kwethluk River, according to a preliminary report from the National Transportation Safety Board.
Blaze Highlander, 47, was conducting a post-maintenance check flight in the Cessna 207 from the company's base at the Bethel airport at the time of the accident. According to the report, the plane appears to have first struck a birch tree about 30 feet tall. It then traveled another 350 feet, landing on its left side in the Kwethluk River. Highlander was the sole occupant, and was killed in the crash.
The plane had "automatic dependent surveillance-broadcast" (ADS-B) equipment aboard, which broadcasts GPS-derived locations to other planes and ground-based receivers linked to the air traffic control system. The plane was transmitting these signals for some of the flight, the NTSB report said. The last signal -- about 6 miles from the crash site -- showed the plane flying at an altitude of 475 feet.
NTSB spokesperson Clint Johnson said it's unclear if Highlander was flying "too low," as terrain in the crash area varies.
Johnson said he doesn't believe weather will prove to be a factor, though it's difficult to know exactly what conditions at the site were at the time of the crash. The closest weather data available is from Bethel, about 40 miles from the crash site, where visibility was "unrestricted," Johnson said.
Highlander left Bethel on the morning of Saturday, May 30, and was reported missing when he didn't return on time.
The following day, the plane's wreckage was discovered. Highlander's body was recovered from the wreckage June 4.
NTSB preliminary reports do not assign a probable cause. More detailed analyses of the plane's engine and ADS-B data are pending, the report said.
The engine, which separated from the rest of the plane, remains submerged in the river, which is too fast and too high to allow its recovery, Johnson said.
River depth is being monitored daily by Yute, Johnson said, and retrieving the engine is a priority in the investigation.
The plane's frame has already been removed from the river.
Since the crash, Johnson said, Yute Air has made changes to how it tests planes, but directed additional questions to the company, which didn't immediately respond to phone calls Tuesday morning.